climate control on L1 charging?

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I agree, I suspect the following:

1. The car's heating and A/C are designed to work using DC.
2. The main heater probably uses the high voltage DC (from the main "traction" battery), to minimize currents and conversion losses.
3. The A/C probably does the same, but uses noticably less power.
4. The seat/steering wheel heater, if we have it, will use the 12-volt system, for safety. But, the 12-volt system gets all of its energy "through" the main traction battery, via a DC-to-DC converter (unless one has the PV panel, and it is adding energy to a non-full 12v battery).
5. Most likely, the only path for AC energy to enter the car will be through the current-limited charger, either 1.4 or 3.3 kW, and the charger will convert that, if needed, to high-voltage DC in an attempt to charge the traction battery, or POSSIBLY to "maintain" a given charge level.
6. The internal charger MIGHT also supply some DC energy when the battery is already "charged", and the requested pre-heat/cool begins, in an attempt to keep the battery from discharging. Of course, it could not if the EVSE was OFF, unplugged, or "timed out".

So, I suspect that the pre-heat/cool WILL use whatever energy it needs from the traction battery, and a powered charger COULD try and supply some (or much) of the energy, and that the pre-heat/cool will (MAYBE, probably) work, using the main battery, even if the car is NOT plugged in.

My 5¢ worth.
 
My company deals with preheat and precool, not in cars, but in commercial buildings. Some of the major factors, which will be a bit different when it comes to cars are:

1. Thermal mass - the amount of heat or cold that is "stored" in the mass of the interior of the space, probably lower in a car
2. Insulation resistance - likely to be lower in a car and thus more loss to the ambient temp outside
3. Solar radiation - This is helps preheat and hurts precool (during the day).
4. Outside air temp - the more temperature differential accross the insulation resistance, the more the losses will be
5. Off peak electricity cost - likely insignificant in car preheat / precool since the small thermal mass and low insulation resistance would preclude long term thermal storage.

All said, I would expect preheat / precool to give some small range advantage because it could "charge up" the small thermal mass of the car while it was on AC power. If the car was disconnected and driven away immediately before the thermal mass had a chance to discharge through the insulation resistance, maybe one would get a slight advantage.
 
The AC uses up to 600W, from one of the economy displays in the LEAF. Does anyone know if the AC can also work as a heat pump, to provide heat in moderate climates?
 
Herm said:
Does anyone know if the AC can also work as a heat pump, to provide heat in moderate climates?
It can not. The heater is separate and uses more power than the AC
 
I have heard from another thread on this website that the heater is a resistive heater, not a heat pump.
Power consumption of the heater can get up to around 5,000 watts, according to this video I made.
http://www.youtube.com/watch?v=Apaf7nGXZt8
The temperature is set to 90 F and the fan is turned up about 3/4 of the way. At 45 seconds you can see the power consumption rising above 4500 watts.

A bit later in the video I keep the temperature setting at 90 F, but I turn down the fan speed but the power consumption stay above 1500 watts.
My video pretty much confirms this as I doubt a car heatpump with a variable speed compressor would take more than 2000 watts max.


So I would have to assume that the climate control system (heater, fan and air conditioner systems) are powered thru the battery pack but the pack can also be receiving juice from a charger at the same time..
 
danwat1234 said:
I have heard from another thread on this website that the heater is a resistive heater, not a heat pump.
Power consumption of the heater can get up to around 5,000 watts, according to this video I made.
http://www.youtube.com/watch?v=Apaf7nGXZt8
The temperature is set to 90 F and the fan is turned up about 3/4 of the way. At 45 seconds you can see the power consumption rising above 4500 watts.

A bit later in the video I keep the temperature setting at 90 F, but I turn down the fan speed but the power consumption stay above 1500 watts.
My video pretty much confirms this as I doubt a car heatpump with a variable speed compressor would take more than 2000 watts max.


So I would have to assume that the climate control system (heater, fan and air conditioner systems) are powered thru the battery pack but the pack can also be receiving juice from a charger at the same time..
According to the service manual, the Leaf heater is a 5kW total unit made up of four elements, all under computer control. Heater power is modulated (PWM) so heat control is not simply 'turn on element 1, now turn on element 2'.
 
danwat1234 said:
I have heard from another thread on this website that the heater is a resistive heater, not a heat pump.
Power consumption of the heater can get up to around 5,000 watts, according to this video I made.
http://www.youtube.com/watch?v=Apaf7nGXZt8" onclick="window.open(this.href);return false;
The temperature is set to 90 F and the fan is turned up about 3/4 of the way. At 45 seconds you can see the power consumption rising above 4500 watts.

A bit later in the video I keep the temperature setting at 90 F, but I turn down the fan speed but the power consumption stay above 1500 watts.
My video pretty much confirms this as I doubt a car heatpump with a variable speed compressor would take more than 2000 watts max.


So I would have to assume that the climate control system (heater, fan and air conditioner systems) are powered thru the battery pack but the pack can also be receiving juice from a charger at the same time..
Had to laugh out loud when you were talking about the controls. The dial next to the speaker switch is not for volume control, but headlight aim. The other one is traction control.
 
You know, there is a simple way to answer this question. I could do it, but I'm too lazy.
  • Step 1 - Buy a Kill-o-Watt or similar device which reads amps and plug the L1 EVSE into it.
  • Step 2 - Plug car into L1 charger
  • Step 3 - Measure current draw (should be around 12 amps)
  • Step 4 - Allow car to completely finish charging cycle.
  • Step 5 - Use iPhone to turn on heater
  • Step 6 - Measure current draw

So, if the current draw from just the heater is less than the current draw from charging the battery, then we'll know that the L1 EVSE is not being used to is full capacity.

However, if you think about it most of your little portable heaters you buy at Wal-Mart for $30 run on regular 110 volt household plus and usually pull between 8 and 12 amps. They also produce quite a lot of heat in order to heat up an entire room. In the case of the leaf, it just needs to heat the interior of the car. So I see no reason why it would need to pull more power than that.

Same true of a window-unit air conditioner. They pull around 12 amps also, so again that should be enough power to cool down a car. Plus I'd be willing to bet the A/C in the Leaf is probably a lot more efficient than a $100 window unit air conditioner.
 
This test should settle the question. Here is what I did/observed:

On a very cold day (55) I turned on the car while it was plugged in (L1) at about 75% charge. I turned on the climate control in Auto and set it to 77 to simulate a remote control activation request.

The on board energy gauges show about 1.2kW used by the climate control. Plus about 120W for Other Systems. Probably about 1.3KW total. The Miles gauge did not drop so it was probably not pulling anything significant from the batteries.

So if its drawing 12A on 120V it has about 1.44kW to work with. Giving a hundred watts for losses in conversion it looks like it is configured to use only shore power (no batteries) to run the heater when on L1. Of course that doesn't leave anything significant left over for charging the main battery bank.
 
Mark510 said:
On a very cold day (55) I turned on the car while it was plugged in (L1) at about 75% charge. I turned on the climate control in Auto and set it to 77 to simulate a remote control activation request.

The on board energy gauges show about 1.2kW used by the climate control. Plus about 120W for Other Systems. Probably about 1.3KW total. The Miles gauge did not drop so it was probably not pulling anything significant from the batteries.

.

Glad you consider 55 very cold :) 43 here this morning.

I noticed something interesting yesterday that tells me the car will use battery power to pre-heat a vehicle even if it is connected to a power source.

Car was charged to 80% overnight on my home L2 Blink EVSE.
6 minutes prior to leaving for work I manually started a pre-heat using carwings. (I left earlier than normal and the timer had not yet kicked in). When I got half way down my driveway I noticed the dash indicated that it would take 10 minutes at 240v to charge the vehicle. Normally that message does not appear until I have driven a mile or more. I used one more bar than normal going to work that day.

I surmised therefore that initially the pre-heat maxes out the heat cycle, probably at close to 6kW, then as the car warms drops down to say 1.5 kW and uses any excess power from the EVSE to top off the battery. Even when connected to an L2 charger it can't deliver the 6kW initial draw given that the charger is rated for 3.3 kW.

On a normal day the pre-heat takes up to 20 minutes prior to my departure, plenty of time to restore the battery to 80% charge during the latter half of the heat cycle if connected to an L2 EVSE.

As for the L1 EVSE, I'm sure that it will suck the battery down initially and will most probably never be able to put it all back by the end of the pre-heat cycle.
 
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